Redox regulation of cytosolic glycerol-3-phosphate dehydrogenase: Cys102 is the target of the redox control and essential for the catalytic activity

Ji Young Kim, Hee Sae Park, Soo Im Kang, Eui Ju Choi, Ick Young Kim

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Cytosolic glycerol-3-phosphate dehydrogenase (cG3PDH) occupies the branch point between the glycolytic pathway and triglyceride biosynthesis. However, the regulatory mechanism of the cG3PDH activity has remained obscure. Here we report that cG3PDH is efficiently inhibited by modification of the thiol group through a redox mechanism. In this study, we found that sodium selenite and nitric oxide (NO) donors such as S-nitroso-N-acetylpenicillamine and 3-morpholinosydnonimine inhibited cG3PDH activity, and that similar effects could be achieved with selenium metabolites such as selenocysteine and selenomethionine. Furthermore, we found that reducing agents, such as dithiothreitol and β-mercaptoethanol, restored the cG3PDH activity suppressed by selenite and NO both in vitro and in cultured cells. Buthionine sulfoximine depleted levels of both reduced glutathione and the oxidized form but had no effect on the suppression of cG3PDH activity by selenite in cultured cells. Moreover, thiol-reactive agents, such as N-ethylmaleimide and o-iodosobenzoic acid, blocked the enzyme activity of cG3PDH through the modification of redox-sensitive cysteine residues in cG3PDH. The inhibitor of NO synthase, L-NG-nitro-arginine, restored the cG3PDH activity inhibited by NO in cultured cells, whereas the inhibitor of guanylyl cyclase, 1H-[1,2,4] oxadiazole[4,3-α] quinoxalin-1-one (ODQ), has no effect. NO directly inhibits cG3PDH activity not via a cGMP-dependent mechanism. Finally, using site-directed mutagenesis, we found that Cys102 of cG3PDH was sensitive to both selenite and NO. From the results, we suggest that cG3PDH is a target of cellular redox regulation.

Original languageEnglish
Pages (from-to)67-74
Number of pages8
JournalBiochimica et Biophysica Acta - General Subjects
Volume1569
Issue number1-3
DOIs
Publication statusPublished - 2002 Jan 15

Keywords

  • Cytosolic glycerol-3-phosphate dehydrogenase
  • Redox mechanism
  • Reducing agent
  • S-Nitroso-N-acetylpenicillamine
  • Sodium selenite
  • Thiol

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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